RESUMEN
We report on the generation of 250mW of coherent 460-nm light by single-pass frequency doubling of the mode-locked picosecond pulses emitted by an InGaAs diode master oscillator power amplifier in periodically poled KTP.
RESUMEN
An internal doubling efficiency of 64% at 2 MW/cm(2)was obtained in a single-pass configuration with an uncoated, 1-cm-long, bulk periodically poled KTP crystal placed outside the resonator of a pulsed, diode-pumped Nd:YAG laser. An average of 4.8W of green light was obtained from a 7.5-W pump beam inside the crystal. Doubling efficiency exceeded 50% at levels of 0.75 MW/cm(2). The measured thermal tolerance of the doubling process (FWHM) was 3.3( degrees )C cm, and the measured temperature tuning coefficient was 0.053 nm/( degrees )C .
RESUMEN
An intracavity critically phase-matched optical parametric oscillator (OPO) was demonstrated with a LiNbO(3) crystal placed inside the resonator of a diode side-pumped Q-switched Nd:YAG laser. The OPO acted as a singly resonating cavity on the signal with a threshold below 10 MW/cm(2). Output energy as high as 640 microJ was observed at the idler wavelength of 3.7 microm, which corresponds to a conversion efficiency of 1.8% from diode light to idler light. Tunability over the wavelength range 3.3-4.15 microm was obtained by rotation of the LiNbO(3) crystal.
RESUMEN
Statistical properties of a He-Ne laser beam (0.63 microm) propagating through atmospheric folded paths of 1 and 12 km were investigated experimentally using direct and heterodyne detection. Measured scintillation histograms, power spectra, time autocorrelations, and phase fluctuations are reported. The turbulence parameters derived from the optical measurements were found to be in good agreement with those obtained from measurements of in situ temperature fluctuations.
RESUMEN
In an attempt to shorten tumor induction time and alter tumor anaplasticity, ductal metaplasia was induced in the submandibular gland of 30 rats by ligation of the duct and artery followed by the implanation of 4-mg pellets of pure DMBA. Control groups consisted of 19-ligated and 15-DMBA implanted rats. The ligate controls showed degeneration and atrophy of the affected gland and replacement of glandular tissue by scar tissue. The DMBA controls followed the expected pattern, with all rats eventually developing well-differentiated squamous cell carcinoma. The CMBA-ligated rats showed a combination of the two processes, each acting separately from the other. There was no difference either in induction time or tumor anaplasticity between the DMBA control rats and the DMBA-ligated rats. It seems that only factors relating to a change in the immunologic response of the host affect the latent period of tumor induction time in submandibular gland carcinogenesis.